凝固型绵羊奶酸奶的发酵特性及活菌数变化

研究凝固型的绵羊奶与牛奶酸奶发酵特性和贮存期特性,利用pH计、酸度滴定、质构仪、电子舌、活菌计数及感官评价对其pH值、滴定酸度、质构特性、味觉特点、活菌数和感官评分进行分析。结果表明：在发酵过程中绵羊奶与牛奶有相同的pH值变化规律,即前2.5 h下降非常缓慢,之后迅速下降,在凝乳前0.5 h下降变缓直到凝乳结束,达到发酵终点的时间分别为5 h和4.5 h;在4 ℃贮存0～24 d期间,酸奶的pH值都在逐渐下降,牛奶酸奶比绵羊奶酸奶下降更大;滴定酸度方面起始时绵羊奶比牛奶高,达到发酵终点时也明显高于牛奶;质构测定结果为YSM（添加益生菌干酪-张发酵的凝固型绵羊奶酸奶）、JDM（嗜热链球菌与保加利亚乳杆菌共同发酵的经典凝固型绵羊奶酸奶）具有更高的硬度和稠度,黏聚性和黏性指数也显著高于JDN（嗜热链球菌与保加利亚乳杆菌共同发酵的经典凝固型牛奶酸奶）,奶的种类为影响酸奶硬度、稠度、黏聚性和黏性指数的主要因素,益生菌干酪-张的添加对这些指标的影响很小;电子舌测定结果为丰富性味感值绵羊奶酸奶明显高于牛奶酸奶,酸感值则低于牛奶酸奶,甜、苦、咸、涩、鲜感值差异不明显;感官评价方面绵羊奶酸奶综合评分高于牛奶酸奶,差异性主要体现在滋味、组织状态和喜爱程度上,在色泽和气味方差异不明显;在4 ℃、21 d贮存期间酸奶的活菌数都在逐渐降低,添加益生菌干酪-张的绵羊奶酸奶活菌数最多,第21天时活菌数分别是普通绵羊奶酸奶和牛奶酸奶的10 倍和100 倍以上,干酪-张对绵羊奶酸奶4 ℃贮存期间活菌数的维持有较好作用。同时,实验结果表明：益生菌干酪-张可以作为发酵剂之一与经典的酸奶发酵剂嗜热链球菌和保加利亚乳杆菌搭配用于凝固型绵羊奶酸奶的制作,以增加其功能价值。     

戴瑞羊、小尾寒羊及其杂交后代乳成分比较分析

为培育我国自主知识产权的新品种奶绵羊,本研究对戴瑞羊(DM)、小尾寒羊(STH)、戴寒杂交F1(F1)和戴寒杂交F2(F2)乳中常规成分、脂肪酸、氨基酸、矿物质和维生素进行了比较分析.结果表明,F1乳的脂肪含量最高,其蛋白质、酪蛋白、固形物和非乳脂固形物以及必需氨基酸含量仅次于STH乳,显著高于DM和F2乳(P<0.0...     

新西兰乳企突破绵羊奶瓶颈

正近日媒体披露,新西兰Maui牧怡的绵羊奶实现突破后,开始进入商业量产阶段。有趣的是,Maui牧怡公司高管团队以华人为主,中国乳业大佬牛根生出任了Maui牧怡公司"首席战略顾问"。据了解,Maui牧怡是一家绵羊奶供应商,2010年,聚焦于奶绵羊基因种群发展问题。在全球顶尖基因专家的技术支持下,Maui牧怡汇集世界顶级奶绵羊品种,培育出新西兰国旗命名的"南十字星"羊种。此品种产奶量     

用羊奶制取奶油的工艺

母羊占我国绵羊头数的一半以上,因此,在用绵羊奶加工各种乳制品时制取美味优质的奶油,这对于满足人民对奶油的需要有着重要的意义。据称,羊奶制成的奶油比起牛奶制成的奶油似有质量较差和不耐保存的缺点。不完全如此,这同它的制取工艺有着密切的关系。     

热处理对乳中CLA含量的影响

目的:研究了不同热处理对乳中CLA含量的影响,同时探讨了UHT奶贮存过程中CLA含量的变化.方法:选用原料奶进行常规巴氏杀菌、煮沸和UHT热处理,分析样品的CLA含量,同时测定UHT奶贮存1、7、14、28d后CLA含量的变化.结果:原料奶中CLA含量最高,为5.306±0.097me/g脂肪酸,UHT奶中CLA含量最低,为4.772±0·180mg/g脂肪酸.下降10.06%.煮沸奶和UHT奶中CLA含量显著低于原料奶(P＜0.05),而常规杀菌奶与原料奶无显著差异(P＞0.05).在保质期内,UHT奶的CLA含量变化差异不显著(P＞0.05).结论:煮沸和UHT热处理会影响奶中CLA含量,UHT奶贮存过程中对CLA含量无显著影响.     

泌乳期间绵羊乳成分及酶凝乳特性变化规律

为探明东弗里生绵羊泌乳期产奶量、乳成分的变化规律及其与酶凝乳特性的相关性，本实验研究了东弗里生绵羊泌乳期间产奶量、乳成分及酶凝乳的硬度、持水力的变化，并对硬度、持水力与乳成分的相关性作分析。结果表明：在整个泌乳期，东弗里生绵羊的产奶量有显著的变化，从泌乳初期产奶量高于整个泌乳期平均产奶量的2.8%，到中期高于平均产奶量的17.1%，末期变为低于平均产奶量的19.9%；绵羊乳的总固体、蛋白质、酪蛋白和脂肪含量以及钙含量在泌乳期显著增加，乳糖含量略有增加，但变化不显著；泌乳期中酶凝乳的硬度有所增加，初期到中期增加比较明显，中期到末期增加变得缓和，持水性在泌乳期有所降低，初期到中期降低比较明显，中期到末期降低变得缓和；酶凝乳的硬度、持水性与绵羊奶的酪蛋白、脂肪、钙含量呈极显著相关（P＜0.01），酶凝乳的硬度会随着酪蛋白、钙含量的增加而增大，随着脂肪含量的增加而减小；酶凝乳的持水性随着酪蛋白、钙含量的增加而降低，随着脂肪含量的增加而增高；硬度和持水性之间呈极显著负相关（P＜0.01）。以上结果可为绵羊奶产品的开发提供参考。     

绵羊正面服装革脱脂的研究

本文分别对澳大利亚、我国的内蒙、华北及嘉兴路的绵羊板皮油脂含量作了试验分析,并对绵羊板皮的脱脂工艺进行了系统研究,探讨了脱脂规律与实验结果.     

发酵和后熟对牦牛奶营养及风味物质的影响

为研究发酵和后熟对牦牛奶营养成分及风味物质的影响,分析了牦牛奶、发酵后牦牛奶和后熟后牦牛奶中的营养成分和挥发性物质种类和相对含量的变化,并进行了营养和品质评价.结果表明,发酵显著降低了牦牛奶中的乳糖含量(P<0.05),降幅为39.43％;发酵还显著促进了牦牛奶中总氨基酸、必需氨基酸、非必需氨基酸和鲜味氨基酸含量的增加...     

法国奶酪 诱惑来袭

在法国,只有通过凝结后沥干而制成的奶制品才可以被称为“奶酪”（Fromage）,以牛奶、山羊奶或绵羊奶为原料,使用未煮熟的奶或经巴斯德灭菌法消毒的奶,整个制作过程经过严格的卫生检验,让每一块入口的奶酪,不仅仅带来法式的口感,更代表了法国对食品安全的绝对严格标准。     

獐奶氨基酸和脂肪酸含量分析及奶胃微生物分离鉴定

獐奶是幼獐的奶胃形成獐宝的基本物质,獐的奶胃是形成獐宝的主要场所。为进一步研究獐宝的体外合成机制,本文采用高效液相色谱和气相色谱法测定了獐奶中氨基酸和脂肪酸含量。并通过传统微生物分离手段对獐的奶胃微生物进行了分离鉴定。通过测定发现,獐奶中的水解氨基酸含量是牛奶的2.73倍。獐奶中丝氨酸、苏氨酸和半胱氨酸等游离氨基酸的含量高于牛奶中的含量,谷氨酸、天冬氨酸、甘氨酸和丙氨酸的含量却低于牛奶中的含量。獐奶中硬脂酸和亚油酸含量为牛奶的2倍多。通过对獐的奶胃微生物的分离和16S r DNA手段鉴定获得20种细菌,这些细菌主要为动物类乳杆菌、肠杆菌和肠球菌类,这些细菌对促进"獐宝"形成起一定的作用。     

掺假羊乳及其制品中牛乳的检测技术研究进展

羊乳具有营养价值高、蛋白质组成更接近人乳、脂肪球直径小及致敏性低等优点, 更利于人体消化吸收, 受到消费者和乳品企业的青睐。近年来我国羊乳产业发展迅速且潜力巨大, 但由于受羊乳产量和养殖规模的限制, 羊乳价格昂贵, 市场中存在羊乳及其制品掺假牛乳的现象, 且掺假手段多样, 难以辨别。为了保证消费者的健康和权益, 保障羊乳市场良性发展, 羊乳及其制品的纯正性、真实性检测已经成为热点研究方向。本文通过分析基于乳中蛋白质、脂肪和核酸差异的羊乳中牛乳掺假检测技术的研究现状, 介绍和探讨了各检测技术的基本原理及其在应用中的优缺点, 同时展望羊乳掺假检测技术的发展方向, 旨在为牛羊乳混合掺假检测技术的进一步发展提供资料参考和思路。     

Nutritional Value and Technological Suitability of Milk from Various Animal Species Used for Dairy Production

Abstract: The analysis of nutritional value and selected traits of technological suitability of milk was performed on the basis of the available literature. This analysis concerned various animal species used for dairy purposes (cattle, buffalo, goats, sheep, camels, donkeys, and horses). It has been stated that a considerable diversity exists in the analyzed parameters and traits of milk, which results in various directions of milk utilization. Cow milk accounts for more than 80% of world milk production. It is the most universal raw material for processing, which is reflected in the broadest spectrum of manufactured products. Sheep and buffalo milk, regarding their high content of protein, including casein, and fat, make a very good raw material for processing, especially cheesemaking. Donkey and horse milk have the most comparable protein composition to human milk (low content of casein, lack of αs₁‐casein fraction and β‐lactoglobulin, and high content of lysozyme). Donkey milk is additionally characterized by a fatty acid profile distinctive from milk of other analyzed animal species. Camel milk also has valuable nutritional properties as it contains a high proportion of antibacterial substances and 30 times higher concentration of vitamin C in comparison to cow milk. The composition of goat milk allows using it as the raw material for dairy processing and also to some extent as a therapeutical product (low content or lack of αs₁‐casein).     

液态羊乳的加工研究进展

进入营养健康时代,消费需求不断升级,功能、营养、个性化的产品越来越受到重视.羊乳一直是人类营养的重要组成部分,与牛乳相比,羊乳的营养价值相对较高,凝乳的形成更柔软,乳脂肪小球的比例更高,致敏性低,与人乳更接近,是许多重要营养素的良好膳食来源.除了羊乳的许多有益作用外,饲养山羊和绵羊的优势,如动物成本较低、对饲料和水的需...     

Meat from Sudan desert sheep and goats: Part 2-Composition of the muscular and fatty tissues

Muscle fibre diameter and proximate chemical compositions were investigated in forty Sudan desert sheep and goats on two treatments—control and fattened. The fatty acid composition of fat depots from the fattened animals was also determined. Sheep had thinner fibres, more intramuscular fat and less muscle protein than goats. Sheep responded to the nutritional treatment by depositing more fat and goats responded by laying down more muscle protein. The fatty acids composition of subcutaneous, kidney and intermuscular fat depots was reasonably similar in both species but goats tended to have more oleic acid in their fat depots than sheep. The results suggest that goat meat is not inferior to mutton from a nutritional viewpoint. Consumption of goat meat should be encouraged in the Sudan, especially within the low-income groups, to meet their needs for protein.     

Sheep Milk: Physicochemical Characteristics and Relevance for Functional Food Development

Sheep milk has a high nutritional value and high concentrations of proteins, fats, minerals, and vitamins, as compared to the milks of other domestic species. The physicochemical and nutritional characteristics of sheep milk can be advantageous for the manufacture of products containing prebiotic ingredients and/or probiotic bacteria, which are major categories in the functional food market. Following this technological trend, this review will address the characteristics and advantages of sheep milk as a potentially functional food, as well as the development of sheep milk dairy products containing prebiotics and/or probiotics.     

特种乳加工技术研究进展

特种乳是指牛乳以外的其它家畜乳,具有独特的口感与营养价值,能满足不同民族及地区消费者的特殊饮乳需求,特种乳的加工技术也是乳品工业的重要组成部分。本文综述了牦牛乳、羊乳、马乳等特种乳及其乳制品的加工技术进展,为特种乳资源的深度开发利用提供参考,以期丰富乳制品品种,推动我国各品种乳的协同发展。     

Past, present, and future perspectives of small ruminant dairy research

The objectives of this paper are to review small ruminant dairy research in relation to the dimensions of the dairy goat and dairy sheep industries in the United States and the world. At least 10 countries depend on goats and sheep for between 30 to 76% of total milk supply. Leading among developed countries is Greece producing 178 kg milk per person per year with 61% from sheep and goats. Most developing countries need research, extension service, and public support to improve apparent productivity of goats and sheep. Domestic supply from all milk sources is <100 kg/person per year, and annual apparent yields average <100 kg of milk/goat, <50 kg of milk/sheep, which makes supplies of animal protein and calcium from domestic sources very low. Statistical data on goat and sheep production for United States are not available. The small population of DHIA tested US dairy goats averaged in recent years >700 kg of milk/goat per year, and some dairy sheep breeds may produce as much as 650 kg/yr. The need for more milk availability appears to be reflected in the dramatic increases of dairy goat populations during the last 20 yr: 52% for the world, 56% for developing, 17% for developed countries, while sheep populations decreased by 3% for the world, by 6% in developed, but increased 14% in developing countries. Research has been sparse on the unique qualities of goat and sheep milk compared with cow milk. Much development work by various agencies has been devoted to reducing mortality and improving feed supplies in harmony with the environment; this work is mostly published in proceedings of scientific meetings, often not in English. Results have shown in many cases that dairy goats and dairy sheep can be very profitable, even in developing countries with difficult climate and topographical conditions.     

山羊乳及其制品营养与功能特性的研究进展

山羊乳及相关制品由于丰富的营养价值和良好的健康功效受到越来越多消费者的关注。山羊乳属于一种资源稀缺型特种乳,与牛乳相比,其干物质含量较高、易消化,且致敏性较低,还是多种生物活性成分的良好来源。因此,山羊乳可用于加工制作适合各种人群的保健性能产品,也可作为益生元和益生菌等功能成分的载体。本文就山羊乳营养成分、功能特性以及加工处理等研究领域的前沿成果进行综述,着重介绍山羊乳相关制品预防与缓解多种疾病的作用与机制,为山羊乳高值化产品的开发提供参考。     

A 100-Year Review: Advances in goat milk research

In the century of research chronicled between 1917 and 2017, dairy goats have gone from simply serving as surrogates to cows to serving as transgenic carriers of human enzymes. Goat milk has been an important part of human nutrition for millennia, in part because of the greater similarity of goat milk to human milk, softer curd formation, higher proportion of small milk fat globules, and different allergenic properties compared with cow milk; however, key nutritional deficiencies limit its suitability for infants. Great attention has been given not only to protein differences between goat and cow milk, but also to fat and enzyme differences, and their effect on the physical and sensory properties of goat milk and milk products. Physiological differences between the species necessitate different techniques for analysis of somatic cell counts, which are naturally higher in goat milk. The high value of goat milk throughout the world has generated a need for a variety of techniques to detect adulteration of goat milk products with cow milk. Advances in all of these areas have been largely documented in the Journal of Dairy Science (JDS), and this review summarizes such advances.     

超高压加工技术在牛乳加工中的应用研究概述

超高压加工技术是非热杀菌技术的一种,在牛乳加工中的应用研究是当前热点。本文概述了非热加工技术的概念、发展和特点,特别针对超高压加工技术在牛乳加工中对微生物、乳蛋白和乳脂肪等成分的影响进行了阐述,并简要分析超高压杀菌设备及其在乳品工业的应用现状。超高压杀菌技术在牛乳加工中具有一定的理论依据和实践经验,值得深入研究和商业化推广应用,本文还展望了超高压技术在乳制品工业中的制约因素和应用前景。